Finding the Fourth Proportional to 78.93, 118.39 and 42.81

Step by Step Solution

1. Step 1: Write the proportion equation
   78.93 : 118.39 = 42.81 : x
2. Step 2: Convert to fraction form
   78.93/118.39 = 42.81/x
3. Step 3: Cross multiply
   78.93x = 118.39 × 42.81
4. Step 4: Simplify right side
   78.93x = 5,068.28
5. Step 5: Solve for x
   x = 5,068.28/78.93
6. Step 6: Final answer
   x = 64.21